Loud-speaker



0 21, 1930. N. umwm LOUD SPEAKER Filed Kay 17,. 1927 i 1 ZZM'M/INVENTOR Patented Oct. 21, 1930 1 noon-es mastication ens Eloy 117,

The present invention spperteins to loud specifiers end peiticulsrly to that class in which vihceting uimeture is surrounded by s n uctusting coil snol is ucteol upon at either end by magnetic poles.

The princiyel object is to ohtsin increased; elliciency loy increasing the nuinhei' of turns in the ectueting coil Without increasing its resistance sndl to oinuinish the magnetic i'eluctonce lay at special design oif armature,

ll attain this end other objects luv the mechcnisno illustration in the accompanying drewing in which Fig, l is en en& elevation of the device Fig. 2 is c section of the some on the line A ll oi Fig. 1, Fig. 3 is on end elevation showing pests cut sway; Fig. l is s top view showing ports removed, end. 5 is s top view of e speciul port.

in the seversl figures of the chewing numeral l olesignetes e llehapci magnet to the inner Poleieces of which are attached the ll shspecl polepieces unvi 3. These polepieces use formed so that the limbs of one ovetlep the limhs oi the other with e space between for the etinetni'e i, until one limb of the polepiece 2 is helovv one the other is shove the corresponcling limbs of the poleiece 3., Aspool 5 containing the actuatvvincling fits in hetween the limbs oi the polepieces and is hel in osition hy the govo ecting edges 6, 6 and 7, i ioime l upon these polepiece limbs, 4

lhe armature l which is s special feature of the presentinvention has at constricteol portion which is surrounded by the spool 5 and enlergei ends which are noted upon by the mugnetic poles. This permits the use oi e spool with s small center and yet l provides it comparatively large orm'eture sun-lace to he acted upon hy the polepieces. Having a spool with at small center permits the use oi s greater number of turns in the vviniing Without increasing the electrical resistence. snqi on increase of eficiency is the resultfl 'llhe spool 5 as shown particularly in Fig. 3 has it slot in one side through which the armature is inserted before Winding.

To provide better insulation end-to diminish the electrostatic capacity of the Wind- V. nnnnsmi, on sinus ing, one or more partitions 8 may he {no videol.

in Fig. l the Wincling on one sicle oi the purtition 8 unol port of the polepiece 3 use removed to show the position of the armsture.

The effective srmstui e 4t es shown in Fig. 5, has on extension port at which may he s, nonmagnetic has cooled to the ui'metui'e,

or it may he iclenticsl sncl integral with the armature The cool oi the extension pelt i remote from the armature, is firmly mounted within the magnet l by means of the bracket Q sci the sold. extension port is given the necessary liesiloility lay being cut thinner nesi' said hrschet,

The acoustic element such es s cliephregm it) is connectei to the cimutuce 4: by moons of the link ll. V

in the instrument heirs illustrated the crmsture hes o, fulcrum Without the spool, but

this form of moisture can he used with s fulcrum Within the spool such as shown in my potent. for telephone receiver elated (3 c toloec 126, 1926 lie. 1,60%251 it uoey he used with o fulcrum st looth cncls oi the spool such as shovvn in Patent l lo. 1,5575% olstecl @ctoher Q0, 1925, or it may be used with any other support, such es shown in my application for telephone receiver filecl August 29, 1925, Social No. 53,350.

The moisture here illustiratecl has en enlergecl or widened portion ct each end hut the some invention can he applied at one cool only if desireol.

in the spool as here illustrated the Windin is separated by s partition into two cells, but if clesii'ed several such partitions could he used.

The improvements, here shown are es ecielly adopted; to louzl speaker purposes ut it is obvious that they can he used in connection with other acoustic devices, such es telephone receivers, telephone transmitters, phonograph recorders, and inductive phonograph reproducei's.

l claim:

is A device of the class described comprising s fined actuating coil, an armature exliil tending through said coil, an enlarged portion at each end of said armature, magnetic poles acting upon the enlarged portions of said armature, and an acoustic element operatively connected with said armature.

2. A device of the class described comprising afixed actuating coil, an armature extending through said coil, an enlarged portion at each end of said armature, U-shaped polepieces inclosing said coil and acting upon the enlarged portions of said armature, and an acoustic element operatively connected with said armature.

3. A. device of the class described comprising a spool containing an actuating coil, an armature extending through said spool, an enlarged portion at one end of said armature le -shaped polepieces inclosing said spool and acting upon the enlarged portion of said armature, projecting edges upon said polepieces to hold said. spool in position, and an acoustic element operatively connected with said armature.

4:. A device or" the class described comprising a spool containing an actuating o'oil, an armature extending through said spool, an enlarged portion at each end of said arniature, li -shaped polepieces inclosing said spool and acting upon the enlarged portions of said armature, projecting edges upon said polepieces to hold said spool in position, and an acoustic element operatively connected with said armature.

5. A device of the class described comprising a fixed actuating coil, having a central opening, an armature extending through said opening and having enlarged portions at either end of said armature larger than said opening, magnetic poles acting upon the enlarged portions of said armature, and an acoustic element operatively connected with said armature.

6. In an acoustic device, a fixed actuating coil a laterally vibratile armatureextending through said coil, an enlarged portion at each end of said armature, and magnetic poles acting upon said enlarged portions.

-7. in an acoustic device, a magnet, a fixed coil disposed in the field of said magnet, and an armature with enlar ed ends disposed in said coil, said armature eing mounted to vibrate in a direction transverse to the greatest dimension of said enlarged ends;

8. In an acoustic device, a magnet, polepieces contacting said magnet, an actuating coil in said polepieces, an armature disposed to be acted upon by both said coil and said magnet, said armature having an enlarged end, and a support for said armature comprising a. resilient member attached at one end to said armature and at its other end to a fixed element.

9. In an acoustic device, a magnet, a coil in operative relation therewith, and an armature with enlarged ends disposed in said coil,

the said enlarged ends being substantially unpolarized when said coil is not energized.

10. In an acoustic device, a magnet, a coil in operative relation therewith, and an armature having enlarged ends mounted to exccute arcnate vibrations in said coil transversely to the greatest dimension of said enlarged ends.

11. In an acoustic device, a magnet, a coil in operative relation therewith, and an armature having enlarged ends mounted to (axe cute arcuate vibrations in said coil transversely of the greatest dimension of said enlarged ends, the support of said armature being fulcrumed outside of said coil.

' NA...THANIEL BALDWN. 

